ENZYMIC DEGRADATION OF CEREAL HEMICELLULOSES III. OLIGOSACCHARIDE PRODUCTION FROM β-GLUCAN

Abstract

Of the two glucodisaccharides, four trisaccharides and eight tetrasaccharides which might be expected to arise by degradation of β‐linked glucose polymer containing irregular arrangements of 1.3‐ and 1.4‐linkages, evidence is presented which suggests that all but one of the tetrasaccharides have been obtained, by enzymic or acidic degradation, from β‐glucans isolated from barley or oats. Enzymic degradation—whether by endo‐β‐glucanase or exo‐β‐glucanase, and whether from the barley or the oat product—gives broadly the same qualitative pattern of oligosaccharide production, though there are minor differences. Oligosaccharides containing only one type of linkage are accompanied by others with mixed linkages, and description is given of the tentative characterization of the various products by a combination of chromatographic and electrophoretic techniques. The molecular constitution of the two glucans cannot be accounted for on the basis of regular alternation of small numbers of the two types of linkage.

The enzymic degradation of laminarin. 3. Some effects of temperature pH and various chemical reagents on fungal laminarinases

“…The pH optima of fl-D-(1-÷3)-glucanases from oats, barley, potato, hyacinth, soya bean, actinomycetes and seaweeds are close to our values (Dillon & O'Colla, 1951;Peat, Thomas & Whelan, 1952;Duncan et al 1956;Preece, Garg & Hoggan, 1960). Polysaccharases from other marine organisms require more alkaline conditions for optimum activity: agarase, pH 6-0 (Yaphe, 1957); oC-L-(1l-2)fucanase, pH 7 0 (Yaphe & Morgan, 1959); carrageeninase, pH (Yaphe & Baxter, 1955); alginase, pH 8-0 (McDougall, 1958).…”